柠檬酸辅助下三水碳酸镁晶须的水合制备研究

摘要

以菱镁矿煅烧所得活性氧化镁为原料,柠檬酸为助剂,采用水合法制备了三水碳酸镁晶须,主要研究柠檬酸用量、热解温度和热解时间对晶体制备过程的影响.利用X射线衍射(XRD)和扫描电镜(SEM)分析了产物的物相组成及微观形貌.结果表明:热解温度90℃,柠檬酸用量0.3% ~3%,热解时间30~120min时,均获得结晶和分散性良好,平均直径为3.5μm的三水碳酸镁晶须;柠檬酸辅助下,热解温度75 ~95℃,得到平均长径比为15的棒状MgCO3·3H2O晶须.柠檬酸对MgCO3·3H2O向4MgCO3· Mg(OH)2·4H2O相转变进程具有抑制作用.%With the magnesia as raw materials,citric acid as additives,MgCO3·3H2O whiskers were synthesized by the hydration method.The influence of the amount of citric acid,temperature,and times on the crystalline process was analyzed.The phase composition and microtopography of the produced samples was characterized by X-ray diffraction (XRD)and scanning electron microscope(SEM).The results show that it is possible to syn-thesize nesquehonite whiskers with good crystallization and homogeneous,average diameter of 3.5μm under temperature of 90℃,the amount of citric acid of 0.3% ~3%,reaction time of 30~120min;and needle-like nesquehonite whiskers with average aspect ratio of 15 under temperature of 75~95℃ and surface-active agent with citric acid.Citric acid has an inhibi-tory effect on the phase transformation process of the nesquehonite.